Plasma fuel reformers reform hydrocarbon fuel into a reformate gas such as hydrogen-rich gas. In the case of an onboard plasma fuel reformer of a vehicle or stationary power generator, the reformate gas produced by the reformer may be utilized as fuel or fuel additive in the operation of an internal combustion engine. The reformate gas may also be utilized to regenerate or otherwise condition an emission abatement device associated with the internal combustion engine or as a fuel for a fuel cell.